The field of the present invention relates to compositions and methods for treating or preventing disease in aquatic animals such as farmed fish (e.g. catfish or tilapia) and crustaceans (e.g., shrimp). In particular, the present invention relates to compositions and methods comprising or utilizing spore forming strains of Bacillus for treating or preventing diseases such as enteric septicemia in aquatic animals such as farmed fish (e.g. catfish or tilapia) and crustaceans (e.g., shrimp).
Recently, attention has focused on the use of probiotics to improve animal health and nutrition. The interest in probiotic bacteria for aquaculture application follows their use in human medicine and agriculture (Fuller and Turvey 1971; Roach and Tannock 1980; Fuller 1987; Smoragiewicz et al. 1993; Fuller 1997), in which microorganisms are generally administered as live supplements in feed (Fuller 1997). The beneficial effect to the host has been reported to be nutritional, immunological, and/or to involve competitive exclusion whereby potential pathogens are outcompeted in the digestive tract (Smoragiewicz et al. 1993). Probiotics have been shown to be effective in controlling various infectious diseases in aquaculture, including furunculosis caused by A. salmonicida in rainbow trout (Irianto and Austin 2002), saprolegniosis by Saprolegnia parasitica in the short-finned eel Anguilla australis (Lategan et al. 2004), edwardsiellosis by Edwardsiella tarda in the European eel Anguilla anguilla (Chang and Liu 2002), lactococcosis and streptococcosis by Lactococcus garvieae and Streptococcus iniae, respectively, in rainbow trout (Brunt and Austin 2005), and disease caused by Vibrio anguillarum in Atlantic cod fry (Gildberg and Mikkelsen 1998). The bacteria used for probiotics include Enterococcus spp., Aeromonas spp., Vibrio spp., and lactic acid bacteria (Gildberg and Mikkelsen 1998; Chang and Liu 2002: Irianto and Austin 2002; Lategan et al. 2004; Brunt and Austin 2005). Most of the probiotic bacteria were isolated from the intestine of aquaculture animals (Gildberg and Mikkelsen 1998; Irianto and Austin 2002; Lategan et al. 2004; Brunt and Austin 2005). Some bacteria isolated from the habitats of aquaculture animals also showed probiotic activity (Rengpipat et al. 1998). The antimicrobial activity against a particular pathogen is used as a primary criterion for selection of potential probiotic bacteria (Rengpipat et al. 1998; Irianto and Austin 2002). The collection of bacterial strains used in this study was derived from previous studies of soil-derived bacteria useful for biological control of diseases in plants and for their plant growth-promoting abilities (Kloepper et al. 2004), as well as bacterial cultures derived from catfish intestinal samples identified in this study.